The First Khmers: Tracing the Roots of a People Born from Many Origins

Beneath the stalactites of Laang Spean, in Battambang province, archaeologists have spent more than sixty years digging through a memory that stretches back several millennia. What the earth reveals there upends the idea of a fixed Khmer identity: Cambodia's first inhabitants did not all spring from the same soil. They arrived in successive waves, from the forests of Sundaland, the rice fields of southern China, and eventually the shores of India.

Artistic reconstruction: a family of Hoabinhian hunter-gatherers moves through the tropical forest of Southeast Asia, roughly ten thousand years ago

The Cave That Holds Cambodia's Memory

It nearly all begins in a limestone cavity perched atop Phnom Teak Treang, in the country's northwest. Discovered in 1965 by prehistorians Cécile and Roland Mourer, Laang Spean cave is today considered the best-documented prehistoric site in Cambodia. It remains the only site in the country where Hoabinhian stone tools have been uncovered within such a precisely established stratigraphy. A Franco-Cambodian mission, bringing together France's National Museum of Natural History and Cambodia's Ministry of Culture, resumed excavations there from 2009 onward.

Beneath five metres of sediment, three major occupation layers are stacked on top of one another: a Neolithic layer, a Hoabinhian layer, and, deeper still, a pre-Hoabinhian layer that remains poorly understood. The most recent dating places the site's Hoabinhian occupation at roughly 12,900 to 5,000 years before present. Animal remains recovered from these layers — bovids, tortoises, molluscs, deer — paint the picture of a hunter-gatherer population able to exploit both humid forest and the surrounding wetlands.

These Hoabinhian men and women, part of a technical culture widespread across mainland Southeast Asia, are more than archaeological silhouettes. Genetic analyses of Hoabinhian skeletons recovered in Laos and Malaysia have linked them to a deeply diverged East Eurasian lineage, related today to Andamanese populations and to certain forest-dwelling groups of the Malay Peninsula. They are, in short, the earliest identifiable inhabitants of present-day Cambodian territory — hunter-gatherers already present several millennia before the advent of agriculture.

A Second Wave: Farmers from Southern China

Cambodia's human landscape shifts roughly 4,000 years ago, with the arrival of an entirely different world: that of the first farmers. Two studies published back to back in 2018 in the journal Science changed the way researchers tell this story. By analysing ancient DNA from skeletons found at several Southeast Asian sites, including Man Bac in Vietnam, geneticists Mark Lipson and Hugh McColl showed that the region's first farmers carried a dual genetic heritage: East Asian ancestry close to southern Chinese farming populations, mixed with a much older Eurasian ancestry characteristic of the Hoabinhian populations already present on the land.

This mixing is not an isolated hypothesis. According to Hugh McColl, a researcher at the University of Copenhagen and co-author of one of these studies, both Hoabinhian hunter-gatherers and farmers from East Asia shaped the genetic diversity found in Southeast Asia today, an input further enriched by later migratory waves. Archaeologist Peter Bellwood, who did much to develop this so-called "two-layer" model, notes that Pleistocene hunter-gatherers remained the region's main occupants until Neolithic farmers from southern China migrated onto the mainland and islands of Southeast Asia around 4,000 to 5,000 years ago.

These newcomers brought with them rice farming, pottery, and above all a language: proto-Austroasiatic, the direct ancestor of modern Khmer. By mixing with the Hoabinhian populations already settled there, they founded a composite lineage that would, centuries later, become the genetic and linguistic bedrock of the Khmer people. Khmer today belongs to one of the continent's oldest language families, spoken from northeastern India all the way to Vietnam.

Angkor Borei, or the Quiet Encounter with India

It is not until the early centuries of our era that a third player enters the story, and its entrance is a dramatic one. At Angkor Borei, in what is now southern Cambodia, rises one of the very first states of mainland Southeast Asia: Funan, known through Chinese chronicles for its thriving trade with India. Archaeology had already established that cultural contact between Indian and local mainland Southeast Asian populations began as early as the 4th century BCE. But in 2022, a study published in Scientific Reports offered far more intimate proof of that contact: DNA.

By analysing the skeleton of an individual buried in the Vat Komnou cemetery at the Angkor Borei site, an international team of geneticists uncovered South Asian ancestry of between 40 and 50 percent in an individual who lived at the very start of the Funan period. Direct radiocarbon dating places this burial between 78 and 234 CE — roughly a millennium earlier than previous estimates based on present-day populations had suggested. The researchers consider populations from southern India to be the most plausible source of this ancestry, and note that this individual shares more genetic affinity with present-day Cambodians than with most other East and Southeast Asian populations.

What crossed the Bay of Bengal to Cambodia's shores, then, was not only a religion, a script, or an art form — it was men and women, whose descendants mixed, generation after generation, with the local population already shaped by the Hoabinhian and Neolithic waves before them.

One People, Many Heritages

From the cave of Laang Spean to the necropolises of Angkor Borei, the story of Cambodia's origins reads like a palimpsest. Underneath, the Hoabinhian hunter-gatherers, present since the late Pleistocene. Above them, the Austroasiatic farmers from southern China, bearers of rice and of the nascent Khmer language. And, on the surface, the later but decisive imprint of India, arriving by sea and trade rather than conquest.

Nothing in this succession of layers points to a "pure" people or a single origin. The Cambodia that would later emerge, in the glory days of Angkor, was already, from its very first centuries, the product of long intermixing — a composite identity, shaped as much by the forests of Southeast Asia as by the maritime routes that, two thousand years ago, already linked the banks of the Mekong to those of the Ganges.